Ultrasonic Versus Mechanical Shear Homogenization
Many customers who are just starting to investigate laboratory homogenization techniques call us and ask what the difference is between Ultrasonic Homogenization and Mechanical Shear or Rotor/Stator Homogenization. As we offer both products, it is fairly simple for us to meet the requirements of all the customers whether they need sonication or mechanical shear technology. Although you may be able to get similar results from both ultrasonic and mechanical homogenizers, the way they create the energy to process the sample is different and can have distinctive effects on the sample and the end result.
Ultrasonic homogenization is created by power that is supplied by electrical energy that is transferred to a probe, usually titanium, where it is converted to mechanical energy. This mechanical energy shows up as longitudinal vibrations at the tip of the probe. Once the energy reaches the tip it causes microscopic vapor bubbles that implode and cause shock waves throughout the sample that cause the processing effect or what is called cavitation.
Ultrasonic probes are solid so they have no tearing or cutting capabilities however they are extremely effective on very small samples as the sample has no chance of hiding in a blade assembly. Sonicators are more effective at processing bacteria and spores along with soil and sediment samples as they have more of an impact effect for breaking the hard walls of these samples. Ultrasonic Homogenizers are also very effective for DNA shearing. However, they do generate more heat than Mechanical Shear Homogenizers so heat sensitive samples must sometimes be cooled.
Rotor/Stator Homogenization is driven by an electrical motor that is used to drive a long shaft with a rotor/stator (blade assembly) attached to the bottom of it. This motor causes rotation of the blade assembly at very high speeds anywhere from 5,000 rpm’s all the way up to 75,000 rpm’s. The blade (rotor) which is rotating pulls the sample into the processing area and then forces it through very sharp windows in the outer blade assembly (stator) to fully and continuously process the sample.
Mechanical shear homogenization is usually better suited to samples that need a tearing or cutting effect on them. Examples of these samples include animal tissue and cells such as mouse organs, tumors, and muscle. It is also very useful for making emulsions and combining powders and liquids along with other general lab applications.
Did you like this article? Stand by, our newest Ultrasonic article entitled “Getting Specific: Ultrasonic Homogenizer Applications” is coming soon!